Method of metal modification under pressure and arrangement to carry out same



March 28, 1967 v, p, poL sHou ET AL METHOD OF METAL MODIFICATION UNDERPRESSURE AND ARRANGEMENT TO CARRY OUT SAME Filed July 16, 1963 f vA 1iEEIIEQQ,

United States Patent i METHOD ()F METAL MODIFICATION UNDER PRESSURE ANDARRANGEMENT TO CARRY OUT SAME Vitalii Petrovich Polishouk, MarkRalrhmilievich Tsin, and Sergei Semenovich Zatouiovsky, all of Kiev,U.S.S.R., assignors to Institut Liteinogo proizvodstva Akademii naukUkrainskoi S.S.R.

Filed July 16, 1963, Ser. No. 295,319 3 Claims. (Cl. 75-45) The presentinvention is related to improving metal properties and moreparticularlyto metal modification. It has now become a common practiceto improve metal properties by treating molten metals by addingmaterials thereto.

Previous methods of metal modification include those in which the liquidmetal is modified under pressure in an autoclave or in a ladle underself-pressure, or the method according to which the metal is modifiedunder air pressure in a stream.

Among the disadvantages of the previous procedures is that the modifieris either introduced into a closed tank of metal under high pressure,that is metal modification according to this method is a batch processin which all metal mass in the tank is under pressure, which fact causeslarge energy consumption; or the modifier is introduced directly into aflowing stream of molten metal under normal pressure, which fact in turncauses costly waste of the modifier and nonuniform addition.

The object of the present invention is to provide a method permittingsaving of the modifier and insuring continuous modification.

Another object of the invention is to provide a method of metalmodification insuring high quality metal modification.

A further object of the invention is to provide an apparatus to carryout the proposed method.

According to the proposed method the metal is allowed to flow in acontinuous stream. The pressure is produced by two electromagneticfields induced by two coils, provided with magnetic cores and enclosedin a ceramic housing, along that portion of the stream to which themodifier is applied.

The method of the invention is illustrated in the accompanying drawing,in which:

FIGURE 1 is a view partly in vertical section and partly in elevation ofan apparatus for practicing the method, and

FIGURE 2 is a horizontal cross-sectional view taken along line AA ofFIGURE 1.

As stated, the drawing shows an apparatus to carry out the proposedmethod of modification. It comprises a vessel 1; an inclined duct 2 foradmitting the liquid metal; a vertical passage 3 to provide an outletfor uncombined modifier vapours; a modification chamber 4 with an inlet5 for admitting the modifier; two coils 6 and 7 with magnetic cores 8and 9, housed in a ceramic casing 16, and an outlet spout 11.

The arrangement functions in the following manner; the coils are primarywindings of singlephase transformers whose common secondary winding isthe ring of liquid metal in the chamber.

The ring of liquid metal extends between the two transformer magneticcores 8 and 9 whose primary coils 6 and 7 are connected in parallel.Thus, current is induced in the liquid metal by the upper coil and thelower coil. Since the arrangement comprises a secondary winding which isliquid metal and which is common to the two primary windings and islocated between the latter, a compressive stress is produced in theliquid metal, due to which fact pressure is applied to the metal along3,31 1,467 Patented Mar. 28, 1967 ice the short length of the streamwhere the modifier is added to the metal, said pressure being dependenton the current flow in the coils. The cross section of the ducts and theoutlet port diameter are determined so as to allow molten cast iron orother metal to fill all the conduits during operation. The modifier isapplied continuously throughout the modification process through theinlet port 5 in any known manner.

On entering the cast iron, the metallic modifier evap orates much slowerthan under air pressure, because the metal in the chamber 4 is underpressure. Modifier vapour bubbles move upwards and treat the metal inchamber 4 and passage 3. Uncompounded vapours are withdrawn throughpassage 3 and pass to the ventilationsystern. The metal treated in theabove described manner is discharged through the outlet passage 11.

As the metal flows down through the chamber 4 at a certain velocity, itentrains the ascending modifier bubbles. Consequently, their passagethrough the metal becomes longer. Adequately chosen pressure in themodification chamber and the velocity of the metal fiow permit high-ratemodifier assimilation in the metal at any temperature of the metal andwith any amount of the modifier applied.

The invention described herein is characterized by the followingadvantages:

(1) The arrangement permits a continuous treatment of liquid metal bymodifier under pressure.

(2) The treatment takes place when the metal is discharged from afurnace into the ladle, and therefore does not require additional time.

(3) The gradual application of the modifier combined with the highpressure in the modification chamber with the opposite flows of modifierbubbles and metal and a relatively high column of metal to be treated,provide best conditions for high-rate modifier assimilation and metalsaturation with the modifier to a large extent.

(4) A possibility to treat any weight of metal and to alter the volumeof metal treated per unit time and the amount of the modifier added.

(5) The absence of moving parts in the modification chamber permitsreliable sealing of the area under the pressure of the liquid metal,which fact permits a safe operation of the arrangement.

(6) The arrangement is small and is installed in a limited space.

(7) The currents induced in the metal heat the metal during thetreatment procedure.

(8) The arrangement is easily controlled and adjusted for a wide rangeof parameters.

(9) The operation of the arrangement can be completely automated by aself-adjusting regulation system.

Although the present invention has been described in connection with thepreferred embodiment, it will be understood that modifications andvariants may occur without departing from the spirit and scope of theinvention.

Such modifications and variants are considered to be within the scope ofthe invention and the appended claims.

What we claim is:

l. A method of continuous treatment of molten metals with additivescomprising: providing a continuous flow of molten metal through a closedchannel defining a treating zone; imposing electromagnetic fields on thecontinuous flow of metal in said closed channel at two axially spacedpoints so as to induce in the liquid metal in said channel two oppositeelectromagnetic forces, which create a high pressure zone in saidchannel between the points where said electromagnetic fields areapplied; continuously supplying additives which are vaporizable at thetemperature of the molten metal to the flowing metal in said highpressure zone, whereby the additives evaporate at a slow rate under theeffect of high pressure, thereby prolonging the time of contact betweenvapors of the additives and the molten metal.

2. An apparatus for continuous treatment of molten metals with additivescomprising: a closed channel having an inlet for admitting molten metaland an outlet for discharging molten metal from said channel; twoelectromagnets positioned to create a high pressure zone in the moltenmetal while it flows through said channel, said electromagnets beingmounted on said channel spaced from each other and producing forceswhich act in 0pposite directions; an opening in said closed channelbetween said electromagnets for continuously feeding said additives tothe molten metal while it is flowing through the high pressure zone ofsaid channel.

3. An apparatus for continuous treatment of molten metal with additivesaccording to claim 2, wherein said closed channel is a flow chamberhaving a annular cross section, and said electromagnets are two coilsarranged adjacent the ends of said chamber and energized from an AC.source and fitted on magnetic cores which project into the spacesurrounded by said chamber.

References Cited by the Examiner UNITED STATES PATENTS BENJAMIN HENRIN,Primary Examiner.

1. A METHOD OF CONTINUOUS TREATMENT OF MOLTEN METALS WITH ADDITIVESCOMPRISING: PROVIDING A CONTINUOUS FLOW OF MOLTEN METAL THROUGH A CLOSEDCHANNEL DEFINING A TREATING ZONE; IMPOSING ELECTROMAGNETIC FIELDS ON THECONTINUOUS FLOW OF METAL IN SAID CLOSED CHANNEL TWO AXIALLY SPACED POINTSO AS TO INDUCE IN THE LIQUID METAL IN SAID CHANNEL TWO OPPOSITEELECTROMAGNETIC FORCES, WHICH CREATE A HIGH PRESSURE ZONE IN SAIDCHANNEL BETWEEN THE POINTS WHERE SAID ELECTROMAGNETIC FIELDS AREAPPLIED; CONTINUOUSLY SUPPLYING ADDITIVES WHICH ARE VAPORIZABLE AT THETEMPERATURE OF THE MOLTEN METAL TO THE FLOWING METAL IN